1. Technical Field
The present invention relates to a tunneling magnetic sensing element including an insulating barrier layer made of Mg—O, and in particular, to a tunneling magnetic sensing element which can achieve improvement in a rate of change in resistance (□R/R).
2. Related Art
A tunneling magnetic sensing element (TMR element) is a device having resistance changed by a tunneling effect. When the magnetization direction of a pinned magnetic layer is antiparallel to the magnetization direction of a free magnetic layer, a tunneling current does not easily flow through an insulating barrier layer provided between the pinned magnetic layer and the free magnetic layer, thereby maximizing the resistance. In contrast, when the magnetization direction of the pinned magnetic layer is parallel to the magnetization direction of the free magnetic layer, the tunneling current easily flows, and thus the resistance is maximized.
As the magnetization direction of the free magnetic layer changes by the effect of an external magnetic field on the basis of this principle, the changes in electrical resistance are detected as changes in voltage so as to detect a leakage magnetic field from a recording medium.
Japanese Unexamined Patent Application Publication Nos. 2000-106462, 2001-84532, and 2001-156357 are examples of the related art.